When molecules overlap: a practical guide to clearer viewport images

A molecular scene can contain all the right information and still be difficult to interpret. Ribbons overlap, nearby structures blend together, and it can be hard to tell which parts are in front. That is a visualization problem, not necessarily a problem with the model. A few real-time rendering effects can make depth and structure easier to read without changing the molecular data.

This guide focuses on a useful goal: improve the readability of a loaded scene while keeping an eye on performance. The examples use SAMSON’s viewport effects, which you can toggle quickly through Visualization > Options and adjust in more detail under Interface > Preferences > Rendering.

Start by revealing depth

Ambient occlusion darkens regions that are less exposed to light. In a molecular scene, this can make folds and close contacts easier to distinguish. Screen-space ambient occlusion is a fast approximation, though its appearance can depend on the camera distance. Object-space ambient occlusion is more realistic but slower.

A simple comparison is often the best way to decide whether it helps: toggle screen-space ambient occlusion on and off while keeping the camera view unchanged. In the example below, the Ribbons model of 1AF6 gains stronger depth cues with the effect enabled.

Make overlapping objects easier to separate

When the challenge is judging the relative position of two objects, shadows can help. They provide another cue about how objects sit in relation to one another. The documentation illustrates this with 1YRF and a graphene sheet: without shadows, their relative positions are harder to perceive; with shadows, the spatial relationship is clearer.

Silhouettes offer a different kind of separation. They outline regions at different depths, which can help a ribbon structure remain legible when its parts overlap. Try enabling silhouettes and setting the thickness to 1 for the documented 1YRF example, then compare the result with the effect off.

Keep edges clean, but watch performance

Jagged edges can distract from structural detail. Anti-aliasing smooths those edges; FXAA is described as an efficient option, and multisampling can be adjusted using the available quality choices. In the documented example, choosing Higher quality enables FXAA and sets multisampling to 2. More rendering work is required from the GPU, however, so anti-aliasing may slow visualization for large systems. If interaction becomes sluggish, reduce the quality setting or turn the effect off while exploring.

A practical order of operations

1. Choose the visual model and framing first. Rendering effects improve the appearance of the current view; they do not replace decisions about what to show.
2. Try ambient occlusion. Check whether added depth shading clarifies folds and close regions.
3. Add shadows or silhouettes if overlap remains confusing. These effects provide different visual cues, so assess them in the context of your scene.
4. Adjust anti-aliasing last. Smooth edges can polish the view, but prioritize responsiveness if you are working with a large system.
5. Compare with effects off. A quick before-and-after check helps ensure that shading and outlines clarify the structure rather than compete with it.

These controls are for interactive viewport appearance. For final-quality offline rendering, use the separate Rendering workflow. For the full effect descriptions and settings, see the SAMSON rendering effects documentation.

Note: SAMSON and all SAMSON Extensions are free for non-commercial use. Get SAMSON.